This invention relates to a piezo-electric oscillator having a piezo-electric vibrator and an oscillation circuit element.
Piezo-electric oscillators are used widely in small information apparatuses such as a HDD (hard disk drive), a mobile computer, or an IC card, and in mobile communications apparatuses such as a portable telephone, a mobile telephone or a paging system.
A piezo-electric oscillator of the related art houses both a piezo-electric vibration piece and an oscillation circuit element in an inner space of a package. Namely, an excitation electrode is provided on the surface of the piezo-electric vibration piece. The excitation electrode is electrically coupled with an electrode film that is routed inside the package, and the electrode film is electrically coupled with the oscillation circuit element. Accordingly, the piezo-electric vibration piece and the oscillation circuit element are electrically coupled, and operation of the piezo-electric vibration piece is controlled by the oscillation circuit element.
However, in recent years, since miniaturization of the piezo-electric oscillator has been progressing spectacularly, it is difficult to house the piezo-electric vibration piece and the oscillation circuit element in the same package, as described above.
Japanese Unexamined Patent Publication No. 2001-320240 attempts to address this problem. FIG. 33 is an exploded perspective view of a piezo-electric oscillator 10 (see Japanese Unexamined Patent Publication No. 2001-320240, for example). The piezo-electric oscillator 10 has a piezo-electric vibrator 1 and an oscillation circuit element 8.
The piezo-electric vibrator 1 houses a piezo-electric vibration piece 4 in an inner space S of a package 2, which is formed by depositing a plurality of substrates made of ceramics, and is sealed with a cover plate 3. Here, an excitation electrode 5 is provided on the surface of the piezo-electric vibration piece 4. The electrode film (not shown), electrically coupled with the excitation electrode 5, is routed using the multi-layered substrates made of ceramics so as to form an electrode pad 6 in an open end face of the package 2.
Then, the oscillation circuit element 8 is mounted on the upper face of the cover plate 3 of the piezo-electric vibrator 1 so as to couple a terminal 9 of the oscillation circuit element 8 with the electrode pad 6 with a bonding wire (not shown). Moreover, the piezo-electric oscillator 10 has at a side a control terminal 7 electrically coupled with a part of the electrode pad 6 by routing the electrode film (not shown) inside the package 2. The data for controlling operation of the piezo-electric vibration piece 4 is written in the oscillation circuit element 8 through the control terminal 7.
Accordingly, because in the piezo-electric oscillator 10 it is not necessary to house the piezo-electric vibration piece 4 and the oscillation circuit element 8 together inside the narrow inner space S, manufacturing of the piezo-electric oscillator 10 will be simple even if miniaturized.